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Isaac-1

SW Louisiana

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Posted: 05/13/22 07:59pm Link  |  Quote  |  Print  |  Notify Moderator

As others have mentioned, we really need to know the specs on your converter, and batteries. I have 420 AH of LiFePo4 Lithium batteries being powered by a standard (Non-Lithium) Progressive Dynamics PD9260 and it works just fine, though might be slightly slower getting to a full charge than if I were to have one of their Lithium specific converters. On the other hand some standard off the shelf Non-lithium converters are not nearly as Lithium battery friendly as my PD-9260

3 tons

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Posted: 05/13/22 09:54pm Link  |  Quote  |  Print  |  Notify Moderator

A standard PD (Progressive Dynamics) converter-charger (if so equipped?) will do the job fine so long as it’s tethered with the optional Charge Wizard dongle, which allows you to kick it into it’s 14.4v Boost mode - perfect for LFP’s….If this is your scenario (??), then a stand-alone charger may not be needed, except (depending on capacity) to enhance battery charge recovery times - just saying…

3 tons

steveh27

Grosse Pointe Woods, MI

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Posted: 05/14/22 03:05am Link  |  Quote  |  Print  |  Notify Moderator

I have 2 100AH LiFePo4 batteries and a PD9235 converter-charger. It works just fine. I do have to push in the boost mode button to really get it charging. It cuts off on its own. While driving the alternator charges it just fine also shutting down when full. I have portable solar panels which also work fine.

theoldwizard1

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Posted: 05/14/22 04:48am Link  |  Quote  |  Print  |  Notify Moderator

steveh27 wrote:

While driving the alternator charges it just fine also shutting down when full.

I question that statement !

Modern vehicle charging system do not supply adequate voltage to properly charge LiFePO4 batteries. That is why DC-DC chargers exist !

theoldwizard1

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Posted: 05/14/22 04:52am Link  |  Quote  |  Print  |  Notify Moderator

3 tons wrote:

“Ditch the old converter and wire the battery to the DC distribution panel.…”

I’m not sure what this means?? …Since he merely replaced the previous battery, wouldn’t the LFP still be connected to the distribution panel??

He said he REPLACED the old converter. It needs to be removed.

3 tons wrote:

Goggles 14.6 volt figure merely refers to the upper charge limit before BMS protective cut-off…From my own experience, LFP’s are happy to charge even in the high thirteens

You will never get a 100% charge without a DC-DC charger.

3 tons

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Posted: 05/14/22 08:45am Link  |  Quote  |  Print  |  Notify Moderator

“You will never get a 100% charge without a DC-DC charger.”

Agreed sorta (if not considering solar), but with LFP’s, with the exception of occasional cell re-balancing, there’s not much point in gaining a full 100% SOC - even the high 13’s is enough to at least get you into the low 90% range, and this is what I do (made practicable due to LFP’s deep Depth of available discharge, or ‘DOD’), which seems a fair enough trade-off to extend longevity…At least that’s my own routine…I don’t bother to charge from the vehicle due to having 660w of rooftop solar…Again (unlike Lead batts) there’s no need to routinely achieve a full 100% SOC, in my view it’s better if you don’t..

3 tons

otrfun

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Posted: 05/14/22 10:06am Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

3 tons wrote:

Goggles 14.6 volt figure merely refers to the upper charge limit before BMS protective cut-off…From my own experience, LFP’s are happy to charge even in the high thirteens
You will never get a 100% charge without a DC-DC charger.
Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate.

Long-term float at =>14.6v can permanently damage a lifepo4. If you're the set-it and forget-it type, a 14.6v single-stage "lithium approved" converter/charger is the worst thing you can use to charge a lifepo4.

3 tons

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Posted: 05/14/22 10:34am Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:

theoldwizard1 wrote:

3 tons wrote:

Goggles 14.6 volt figure merely refers to the upper charge limit before BMS protective cut-off…From my own experience, LFP’s are happy to charge even in the high thirteens
You will never get a 100% charge without a DC-DC charger.
Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate.

Long-term float at =>14.6v can permanently damage a lifepo4. If you're the set-it and forget-it type, a 14.6v single-stage "lithium approved" converter/charger is the worst thing you can use to charge a lifepo4.


Agreed, X2

3 tons

theoldwizard1

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Posted: 05/14/22 02:25pm Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:

theoldwizard1 wrote:

You will never get a 100% charge without a DC-DC charger.

Why would you need or want a 100% charge (14.6v) to begin with? Unlike lead-cell batteries, lifepo4's subjected to 100% SOC (14.6v) on a constant, short-term basis experience reduced cycle life. 13.6v will still net 99% SOC (and a higher cycle life), although at a slower charge rate.

Long-term float at =>14.6v can permanently damage a lifepo4.

I never said anything about long term float at that voltage. The point of a DC-DC charger is to give the correct voltage at the correct time during the charging cycle.

3 tons

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Posted: 05/14/22 03:55pm Link  |  Quote  |  Print  |  Notify Moderator

Yep, a dc to dc charger can do exactly that, but if one opts to do such I would only suggest a cut-off switch between the vehicle and the camper to guard against prolonged charging [emoticon]

3 tons

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